The organic light-emitting diode (OLED, or called organic electroluminescence) technology is always considered as one of the most competitive luminescence and display technologies in the next century. However, in the aspect of application of the display, the OLED display seems to have been seriously challenged in terms of enlargement and productivity since commercialization of the PLOLED display published by Pioneer in 1996. Serious challenges mainly come from two aspects, one is the TFT backboard of an active matrix, and the other is the manufacture procedure and encapsulation issue of the organic material. The manufacture procedure of the organic material mainly includes an evaporation plating procedure and a solution manufacture procedure. For the enlarged substrate, the vacuum thermal evaporation plating technology is confronted with great defects, for example, the light-shielding plate is easily affected by the high-temperature environment in the process flow so as to shift, causing that it is difficult to maintain a uniform deposition rate on the substrate. The solution manufacture procedure employs the inkjet printing technology. Therein, the inkjet printing technology enables the formation of a thin film layer by homogeneously depositing the liquid organic material. Therefore, such technology can theoretically better solve the large-size problem.
The inkjet printing is classified into continuous printing and non-continuous printing. The continuous printing mode belongs to a mask-free, contactless manufacture procedure, which has the advantages of performing successive printing, continuously and stably spraying ink due to the larger bore without blocking the nozzle, having high yield, and facilitating enlargement while having a large degree of freedom of the ink composition. However, during the process of continuous printing, it is required to spray ink to several rows of pixels during one printing cycle, and spray ink to other several rows of pixels during the next printing cycle. Successive printing is performed by cycling and repeating the above steps to realize spraying of the whole substrate.
Moreover, during the continuous printing, ink droplets would also drip on the bank between pixels. However, the conventional bank of the prior art would involve the phenomenon of unevenness in the metal wiring and TFT areas, leaving ink droplets in the areas and consequently changing the surface hydrophobic property of the areas. When other film layers are further printed subsequently, more ink is likely to remain, so that further affects the homogeneity of ink within pixels or causes a cross-color phenomenon between adjacent pixels.
Therefore, there is a demand for an improved technology to solve the above problems in the prior art.